EGR malfunction detection system

Abstract

An EGR malfunction detection system includes an EGR valve configured to open and close an exhaust recirculation path for recirculating an exhaust gas from an exhaust channel to an intake channel of an engine, a measurement unit configured to measure an intake pressure inside the intake channel, a valve controller configured to control the EGR valve, and a malfunction detector configured to detect an anomaly in the exhaust recirculation path in accordance with a measurement unit output and a valve controller output. The malfunction detector determines whether the EGR valve is stuck in accordance with the intake pressures measured when the EGR valve is controlled to open and close. If the EGR valve is stuck, the malfunction detector determines whether the EGR valve is stuck in an open state, stuck in a closed state, or stuck in an intermediate state by comparing the measured pressure with predetermined thresholds.

The invention claimed is: 
     
       1. An EGR malfunction detection system comprising:
 an EGR valve configured to open and close an exhaust recirculation path for recirculating an exhaust gas from an exhaust channel to an intake channel of an engine; 
 a valve controller configured to control the EGR valve; 
 an intake pressure sensor configured to measure a first intake pressure inside the intake channel when the EGR valve is controlled to be in a closed state by the valve controller, and measure a second intake pressure inside the intake channel when the EGR valve is controlled to be in an open state by the valve controller; and 
 a processor configured to detect an anomaly in the exhaust recirculation path in accordance with an output from the intake pressures sensor and an output from the valve controller, wherein 
 the processor determines that the EGR valve is stuck in an open state and outputs a first signal indicating that the EGR valve is stuck in the open state, when the first intake pressure is larger than a first threshold and the second intake pressure is larger than a second threshold that is larger than the first threshold, 
 the processor determines that the EGR valve is stuck in the closed state and outputs a second signal indicating that the EGR valve is stuck in the closed state, when the first intake pressure is smaller than the first threshold and the second intake pressure is smaller than the second threshold, and 
 the processor determines that the EGR valve is stuck in an intermediate state and outputs both the first signal and the second signal indicating that the EGR valve is stuck in the intermediate state, when the first intake pressure is larger than the first threshold and the second intake pressure is smaller than the second threshold. 
 
     
     
       2. An EGR malfunction detection system comprising:
 an EGR valve configured to open and close an exhaust recirculation path for recirculating an exhaust gas from an exhaust channel to an intake channel of an engine; 
 a controller configured to control the EGR valve; 
 a sensor configured to measure a first intake pressure inside the intake channel when the EGR valve is controlled to be in a closed state by the controller, and measure a second intake pressure inside the intake channel when the EGR valve is controlled to be in an open state by the controller; and 
 circuitry configured to
 detect an anomaly in the exhaust recirculation path in accordance with an output from the sensor and an output from the controller, wherein 
 
 the circuitry determines that the EGR valve is stuck in an open state and outputs a first signal indicating that the EGR valve is stuck in the open state, when the first intake pressure is larger than a first threshold and the second intake pressure is larger than a second threshold that is larger than the first threshold, 
 the circuitry determines that the EGR valve is stuck in the closed state and outputs a second signal indicating that the EGR valve is stuck in the closed state, when the first intake pressure is smaller than the first threshold and the second intake pressure is smaller than the second threshold, and 
 the circuitry determines that the EGR valve is stuck in an intermediate state and outputs both the first signal and the second signal indicating that the EGR valve is stuck in the intermediate state, when the first intake pressure is larger than the first threshold and the second intake pressure is smaller than the second threshold.